I thought a good source book would be Critical Law, filled with optional critical tables. A-E for No Armor, A-E for Soft Leather, et al, including A-E for LA, SL, even I and II (if that makes sense).
The book could easily be 120 pages. Any volunteers to write the critical tables?
I also thought an optional crit resolution system could be created. When a crit is scored versus a specific AT, a range of possible damge is rolled for with d10(s), covering hits per round, stun, activity penaltys, bone/muscle/nerve/organ dame, etc. This would create variable results for the same critical result rolls but be kinda slow and cumbersome since it would require 3+ d10 rolls.